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| 1 | +package com.examplehub.leetcode.middle; |
| 2 | + |
| 3 | +/** |
| 4 | + * https://leetcode.com/problems/valid-sudoku/ |
| 5 | + */ |
| 6 | +public class ValidSudoku { |
| 7 | + public static boolean solution1(char[][] board) { |
| 8 | + |
| 9 | + //travel all rows to check |
| 10 | + for (int i = 0; i < 9; i++) { |
| 11 | + int[] digitTable = new int[10]; |
| 12 | + for (int j = 0; j < 9; j++) { |
| 13 | + if (board[i][j] != '.') { |
| 14 | + digitTable[board[i][j] - '0']++; |
| 15 | + } |
| 16 | + } |
| 17 | + if (containsRepeat(digitTable)) { |
| 18 | + return false; |
| 19 | + } |
| 20 | + } |
| 21 | + |
| 22 | + //travel all columns to check |
| 23 | + for (int i = 0; i < 9; i++) { |
| 24 | + int[] digitTable = new int[10]; |
| 25 | + for (int j = 0; j < 9; j++) { |
| 26 | + if (board[j][i] != '.') { |
| 27 | + digitTable[board[j][i] - '0']++; |
| 28 | + } |
| 29 | + } |
| 30 | + if (containsRepeat(digitTable)) { |
| 31 | + return false; |
| 32 | + } |
| 33 | + } |
| 34 | + |
| 35 | + //travel all sub-box |
| 36 | + //TODO |
| 37 | + return true; |
| 38 | + } |
| 39 | + |
| 40 | + public static boolean containsRepeat(int[] table) { |
| 41 | + for (int num : table) { |
| 42 | + if (num > 1) { |
| 43 | + return true; |
| 44 | + } |
| 45 | + } |
| 46 | + return false; |
| 47 | + } |
| 48 | + |
| 49 | + public static boolean solution2(char[][] board) { |
| 50 | + int[][] rows = new int[9][9]; |
| 51 | + int[][] cols = new int[9][9]; |
| 52 | + int[][][] subBoxes = new int[3][3][9]; |
| 53 | + for (int i = 0; i < 9; ++i) { |
| 54 | + for (int j = 0; j < 9; ++j) { |
| 55 | + if (board[i][j] != '.') { |
| 56 | + int index = board[i][j] - '1'; |
| 57 | + rows[i][index]++; |
| 58 | + cols[j][index]++; |
| 59 | + subBoxes[i / 3][j / 3][index]++; |
| 60 | + if (rows[i][index] > 1 || cols[j][index] > 1 || subBoxes[i / 3][j / 3][index] > 1) { |
| 61 | + return false; |
| 62 | + } |
| 63 | + } |
| 64 | + } |
| 65 | + } |
| 66 | + return true; |
| 67 | + } |
| 68 | +} |
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